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EC number: 210-535-3 | CAS number: 617-86-7
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Endpoint summary
Administrative data
Key value for chemical safety assessment
Genetic toxicity in vitro
Description of key information
Gene mutation (Bacterial reverse
mutation assay / Ames test): negative with and without metabolic
activation in S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
(OECD 471) (LPT, 2002).
Cytogenicity in mammalian cells: read across from tetramethylsilane:
negative with and without metabolic activation in Chinese hamster lung
fibroblasts (V79) (OECD 473) (Hüls, 1998).
Cytogenicity in mammalian cells: read across from trimethylsilane:
negative with and without metabolic activation in CHL/IU cells (OECD
473) (Japan Bioassay Research Center, 2001).
Mutagenicity in mammalian cells: read across from tetramethylsilane:
negative with and without metabolic activation in Chinese hamster ovary
cells (OECD 476) (Hüls, 1999).
The studies were conducted according to appropriate OECD guidelines, or the Japanese equivalent and under GLP.
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (negative)
Genetic toxicity in vivo
Endpoint conclusion
- Endpoint conclusion:
- no study available
Additional information
Triethylsilane has been tested for mutagenicity to bacteria, in a study which was conducted according to the OECD TG 471 and in compliance with GLP (LPT, 2002). No evidence of a test-substance related increase in the number of revertants was observed with or without metabolic activation in Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 or TA 1537 in the initial or the repeat experiments up to cytotoxic concentrations. Appropriate positive and solvent controls were included and gave the expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.
Information on cytogenicity is available from an assay using tetramethylsilane, which has been tested in a valid and reliable study according to OECD 473 and under GLP (Hüls, 1998). The volatility of the substance was taken into account in the study: exposure was in sealed flasks and an analytical determination of the concentrations by head space analysis was carried out at the end of the incubation period. No increase in the number of cells with aberrations was observed. Positive and vehicle controls produced expected results. It is concluded that the test substance is negative for the induction of chromosome aberrations under the conditions of the test.
Further information on cytogenicity is available from a second surrogate substance, trimethylsilane, which has been tested according to a national standard method (Japanese) that is equivalent to OECD 473, and in compliance with GLP (Japan Bioassay Research Center, 2001). No increase in the incidence of chromosome aberrations was observed when tested using a gas exposure method at concentrations up to 80% with and without metabolic activation in Chinese hamster lung cells. Appropriate vehicle and positive controls were used and gave expected results. It is concluded that the test material is negative for the induction of chromosome aberrations under the conditions of the test.
Information on mutagenicity to mammalian cells comes from a study on the structural analogue tetramethylsilane, which has been tested in a valid and reliable study according to OECD 476 and under GLP (Hüls, 1999). The volatility of the substance was taken into account in the study: exposure was in sealed flasks and an analytical determination of the concentrations by head space analysis was carried out at the end of the incubation period. The statistically significant increase in the number of revertants was neither dose related nor exceeding historical negative control values, and the increase in the presence of metabolic activation was not reproducible. It is concluded that the test substance is negative for mutagenicity to mammalian cells under the conditions of the test.
To reduce animal testing REACH recommends to make use of a read-across approach where appropriate based on the high accordance in properties relevant for the specific endpoint. In the case of genetic toxicity the presence or absence of functional groups that are known to be related to genetic toxicity is considered important, as the presence or absence of reactive groups and molecular substructures is associated with mutagenic and carcinogenic properties of chemicals (Benigni et al., 2008). Consideration is therefore given to the structural similarity, particularly presence or absence of structural alerts for genetic toxicity, when selecting surrogate substances for genetic toxicity endpoints. In the following paragraphs the proposed read-across from trimethylsilane and tetramethylsilane to triethylsilane is evaluated point by point. Further information is given in the report attached to section 13 PFA 2013aa.
Read-across hypothesis
The hypothesis is that source and target substances have similar toxicological properties because they are structurally similar and have similar physicochemical properties.
The substances are hydrolytically stable (triethylsilane, trimethylsilane and tetramethylsilane have half-lives in water of days) so reaction products do not need to be considered for the human health hazard assessment of these substances.
Triethylsilane reacts slowly in water with measured hydrolysis half-lives of 218 hours at pH 4 and 25°C, 377 hours at pH 7 and 20°C and 56.8 hours at pH 9 and 20°C in accordance with OECD 111. The products of hydrolysis are triethylsilanol and hydrogen.
Trimethylsilane reacts slowly in water, with a measured hydrolysis half-life of about 3 days at 24.7°C. The reaction products are trimethylsilanol and hydrogen
Tetramethylsilane has no structural groups that make it susceptible to hydrolysis, so it is stable in water.
Read-across justification
(a) Structural similarity
The registration and read-across substances are structurally similar and are members of an analogue group of alkylsilanes. All contain a silicon atom to which is attached three or four alkyl groups.
For the registered substance there are three ethyl groups, for trimethylsilane there are three methyl groups and for tetramethylsilane there are four methyl groups.
(b) Similar hydrolytic stability
Triethylsilane, trimethylsilane and tetramethylsilane are all hydrolytically stable (half-lives of days)
(c) Lack of structural alerts
None of the substances have structural alerts for genotoxicity (Benigni et al, 2008).
Tetramethylsilane and trimethylsilane were chosen as read-across substance as they are structurally similar to the registered substance and none of the substances has any functional groups that are associated with genetic toxicity. The genetic toxicity data available for other structurally similar substances are summarised in the table below.
Genetic toxicity data available for silanes
CASnumber |
ECnumber |
ChemicalName |
Bacterial mutagenicity |
In vitro mammalian cytogenicity |
In vitro mammalian mutagenicity |
In vivo genotox |
75-76-3 |
200-899-1 |
Tetramethylsilane |
Negative |
Negative |
Negative |
|
617-86-7 |
210-535-3 |
Triethylsilane |
Negative |
|
|
|
631-36-7 |
211-155-0 |
Tetraethylsilane |
No data |
|
|
|
992-94-9 |
213-598-5 |
Methylsilane |
No data |
|
|
|
993-07-7 |
213-603-0 |
Trimethylsilane |
Negative |
Negative |
|
|
7803-62-5 |
232-263-4 |
Silane |
Positive* (+/- MA) |
|
|
|
29681-57-0 |
n/a | t-butyl(dimethyl)silane | Negative | Negative |
* This is a reliability 4 result (not assignable).
References:
Benigni et al (2008). The Benigni/Bossa rule base for mutagenicity and carcinogenicity. JR Scientific report EUR 23241 EN
PFA (2013aa). Peter Fisk Associates, Genotox Analogue Report, PFA.300.004.001.
Justification for classification or non-classification
Based on the available data on triethylsilane, tetramethylsilane and trimethylsilane, triethylsilane does not require classification for genetic toxicity according to Regulation (EC) No 1272/2008.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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